A. Field of the Invention
The present invention relates to a modularized carriage for a contact image sensor module (hereinafter referred to as the CIS module), especially to a modularized carriage having shock absorber struts for allowing a CIS module to contact tightly with the bottom surface side of a sheet table. The modularized carriage can simplify the assembly and adjustment of the CIS scanner and improve the image quality of images.
B. Description of the Prior Art
The scene depth of a conventional contact image sensor is only about 0.3 mm. Any manufacturing error or structure distortion will easily shift the document sheet away from the focus. Referring to FIG. 1, to keep the document sheet positioned within such a short scene depth, the conventional carriage 2 contains an internal spring 4 at the bottom of the carriage. The function of the internal spring 4 is to lift the contact image sensor module 1 up to contact the bottom surface side of the sheet table 6. A contact image sensor module 1 is loaded in a fitting carriage 2. When the carriage 2 is supported by a guiding device 3, the CIS module 1 can tightly contact the bottom surface side of the sheet table 6 with sliding blocks 5a, 5b interposed therebetween while being driven by the guiding device 3. With the spring 4, the CIS module 1 can tightly contact the bottom surface side of the sheet table 6 to keep the document sheet in focus even if the housing is distorted. However, for convenience of assembly, the conventional structure as illustrated in FIG. 1 still has a few drawbacks. For instance, the spring 4 must be located precisely and firmly at the bottom center of the carriage 2. In addition, the guiding device 3 must be carefully installed to keep the carriage 2 in balance. It would be desirable to simplify the structure of the conventional CIS module and make assembly easier.
The primary object of the present invention is to provide a modularized carriage having shock absorber struts for controlling a document staying within the scene depth of the CIS module, thereby to improve the picture quality of the images.
It is another object of the present invention to provide a modularized carriage having shock absorber struts which is adaptable for various types of CIS modules, thereby simplifying the assembly and readjustment procedures of the CIS scanner.
It is yet another object of the present invention to provide a modularized carriage which is easily adaptable for various driving and guiding structures of flatbed scanners, thereby simplifying assembly procedure and further reducing the maintenance fees and manufacturing costs.
In accordance with the invention, a modularized carriage having a plurality of shock absorber struts is provided for allowing the CIS module to tightly contact the bottom surface side of the sheet table. The carriage has a plurality of holes formed on its bottom side for the shock absorber struts. The bottom ends of the shock absorber struts are fixed to the bottom of the carriage. The shock absorber struts pass through the holes for supporting the CIS module in a manner that the CIS module can tightly contact the bottom surface side of the sheet table. Thus, the document can be controlled to stay within the scene depth of the CIS module. Since the present invention is a modularized carriage which is adaptable for various types of CIS modules and transmission mechanisms, the present invention can make the assembly procedure more convenient. The modularized carriage also helps to simplify the inner structure of the CIS scanner and reduces the size of the CIS scanner.